While Vermont sportsmen spend November and December hunting deer, Lyndon State College biology professor Alan Giese is busy hunting deer ticks. He tromps through the woods armed with a white flannel sheet, waving it like a flag over brush so the fabric picks up specimens.

It may not sound scientific, but Giese is surveying five locations along the Connecticut River for deer ticks, potential carriers of Lyme disease, for what he hopes will become Vermont’s first systematic tick-population study. He wants to assign hard data to a trend that scientists and public health officials have observed for years: the spread of deer ticks — and Lyme disease — throughout Vermont.

Giese and a student research assistant started their work last spring. They had planned to be done by now, but, thanks to an unusually warm autumn, the research project and its blood-sucking subjects have stayed active longer than normal this year.

“We expected them to shut down in mid-November, and they haven’t,” Giese says, noting that fall is peak season for adult-stage deer ticks. Giese warns that ticks won’t go underground until night temperatures drop below freezing — and stay there. Meterologists are forecasting warm weather for much of the next week.

A decade ago, Lyme was virtually unheard of in Vermont. In 2000, the state Department of Health recorded just 40 cases, two-thirds of them likely contracted out of state. Yet by 2009, there were 408 confirmed and probable cases, with three-quarters of them determined to have originated in Vermont.

After several years of climbing Lyme rates, 2010 saw a slight dip, to 356 cases, and health officials cautiously hoped that better prevention was causing the disease rates to plateau.

Instead, 2011 is shaping up to be the worst year yet: As of last week, there were more than 500 confirmed and probable cases, according to Erica Berl, an epidemiologist with the Vermont Department of Health.